A method called a fusion process is conventionally known as a manufacturing method of a high-quality glass sheet (for example, see Patent Document 1). The fusion process is a method in which molten glass is run down along both side surfaces of a molded body with a cross section of a wedge shape converging downward and also the molten glass is joined and integrated just under a lower edge part of the molded body and while cooling an integrated sheet-shaped glass ribbon, the glass ribbon is drawn downward and molded.
Patent Document 1 describes the fact that in order to inhibit molten glass running down from contracting in a width direction by surface tension, the vicinity of both right and left ends of both side surfaces of a molded body is provided with a web-like member and an extension member intersecting with the web-like member and downward inclined to the web-like member. The end in the width direction of the molten glass runs along a surface of the web-like member and then runs along a surface of the extension member.
Patent Document 2 describes the fact that in order to inhibit molten glass running down from contracting in a width direction by surface tension, the vicinity of both right and left ends of both side surfaces (front and back surfaces) of a molded body is provided with a guide wall for integrally coupling the front and back at the lower edge of the molded body and a triangular fin-like projection body in which two sides are fixed in contact with an inner wall of the lower end of the guide wall and the lower edge of the molded body. The end in the width direction of the molten glass contacts with the fin-like projection body and wets, whereby a force by which the molten glass is expanded outward is exerted and the molten glass can be inhibited from contracting inward.